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1138 lines
28 KiB
1138 lines
28 KiB
/****************************************************************************** |
|
* gntdev.c |
|
* |
|
* Device for accessing (in user-space) pages that have been granted by other |
|
* domains. |
|
* |
|
* Copyright (c) 2006-2007, D G Murray. |
|
* (c) 2009 Gerd Hoffmann <[email protected]> |
|
* (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc. |
|
* |
|
* This program is distributed in the hope that it will be useful, |
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of |
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
|
* GNU General Public License for more details. |
|
* |
|
* You should have received a copy of the GNU General Public License |
|
* along with this program; if not, write to the Free Software |
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
|
*/ |
|
|
|
#undef DEBUG |
|
|
|
#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt |
|
|
|
#include <linux/dma-mapping.h> |
|
#include <linux/module.h> |
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#include <linux/kernel.h> |
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#include <linux/init.h> |
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#include <linux/miscdevice.h> |
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#include <linux/fs.h> |
|
#include <linux/uaccess.h> |
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#include <linux/sched.h> |
|
#include <linux/sched/mm.h> |
|
#include <linux/spinlock.h> |
|
#include <linux/slab.h> |
|
#include <linux/highmem.h> |
|
#include <linux/refcount.h> |
|
|
|
#include <xen/xen.h> |
|
#include <xen/grant_table.h> |
|
#include <xen/balloon.h> |
|
#include <xen/gntdev.h> |
|
#include <xen/events.h> |
|
#include <xen/page.h> |
|
#include <asm/xen/hypervisor.h> |
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#include <asm/xen/hypercall.h> |
|
|
|
#include "gntdev-common.h" |
|
#ifdef CONFIG_XEN_GNTDEV_DMABUF |
|
#include "gntdev-dmabuf.h" |
|
#endif |
|
|
|
MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("Derek G. Murray <[email protected]>, " |
|
"Gerd Hoffmann <[email protected]>"); |
|
MODULE_DESCRIPTION("User-space granted page access driver"); |
|
|
|
static unsigned int limit = 64*1024; |
|
module_param(limit, uint, 0644); |
|
MODULE_PARM_DESC(limit, |
|
"Maximum number of grants that may be mapped by one mapping request"); |
|
|
|
static int use_ptemod; |
|
|
|
static int unmap_grant_pages(struct gntdev_grant_map *map, |
|
int offset, int pages); |
|
|
|
static struct miscdevice gntdev_miscdev; |
|
|
|
/* ------------------------------------------------------------------ */ |
|
|
|
bool gntdev_test_page_count(unsigned int count) |
|
{ |
|
return !count || count > limit; |
|
} |
|
|
|
static void gntdev_print_maps(struct gntdev_priv *priv, |
|
char *text, int text_index) |
|
{ |
|
#ifdef DEBUG |
|
struct gntdev_grant_map *map; |
|
|
|
pr_debug("%s: maps list (priv %p)\n", __func__, priv); |
|
list_for_each_entry(map, &priv->maps, next) |
|
pr_debug(" index %2d, count %2d %s\n", |
|
map->index, map->count, |
|
map->index == text_index && text ? text : ""); |
|
#endif |
|
} |
|
|
|
static void gntdev_free_map(struct gntdev_grant_map *map) |
|
{ |
|
if (map == NULL) |
|
return; |
|
|
|
#ifdef CONFIG_XEN_GRANT_DMA_ALLOC |
|
if (map->dma_vaddr) { |
|
struct gnttab_dma_alloc_args args; |
|
|
|
args.dev = map->dma_dev; |
|
args.coherent = !!(map->dma_flags & GNTDEV_DMA_FLAG_COHERENT); |
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args.nr_pages = map->count; |
|
args.pages = map->pages; |
|
args.frames = map->frames; |
|
args.vaddr = map->dma_vaddr; |
|
args.dev_bus_addr = map->dma_bus_addr; |
|
|
|
gnttab_dma_free_pages(&args); |
|
} else |
|
#endif |
|
if (map->pages) |
|
gnttab_free_pages(map->count, map->pages); |
|
|
|
#ifdef CONFIG_XEN_GRANT_DMA_ALLOC |
|
kvfree(map->frames); |
|
#endif |
|
kvfree(map->pages); |
|
kvfree(map->grants); |
|
kvfree(map->map_ops); |
|
kvfree(map->unmap_ops); |
|
kvfree(map->kmap_ops); |
|
kvfree(map->kunmap_ops); |
|
kfree(map); |
|
} |
|
|
|
struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count, |
|
int dma_flags) |
|
{ |
|
struct gntdev_grant_map *add; |
|
int i; |
|
|
|
add = kzalloc(sizeof(*add), GFP_KERNEL); |
|
if (NULL == add) |
|
return NULL; |
|
|
|
add->grants = kvmalloc_array(count, sizeof(add->grants[0]), |
|
GFP_KERNEL); |
|
add->map_ops = kvmalloc_array(count, sizeof(add->map_ops[0]), |
|
GFP_KERNEL); |
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add->unmap_ops = kvmalloc_array(count, sizeof(add->unmap_ops[0]), |
|
GFP_KERNEL); |
|
add->pages = kvcalloc(count, sizeof(add->pages[0]), GFP_KERNEL); |
|
if (NULL == add->grants || |
|
NULL == add->map_ops || |
|
NULL == add->unmap_ops || |
|
NULL == add->pages) |
|
goto err; |
|
if (use_ptemod) { |
|
add->kmap_ops = kvmalloc_array(count, sizeof(add->kmap_ops[0]), |
|
GFP_KERNEL); |
|
add->kunmap_ops = kvmalloc_array(count, sizeof(add->kunmap_ops[0]), |
|
GFP_KERNEL); |
|
if (NULL == add->kmap_ops || NULL == add->kunmap_ops) |
|
goto err; |
|
} |
|
|
|
#ifdef CONFIG_XEN_GRANT_DMA_ALLOC |
|
add->dma_flags = dma_flags; |
|
|
|
/* |
|
* Check if this mapping is requested to be backed |
|
* by a DMA buffer. |
|
*/ |
|
if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) { |
|
struct gnttab_dma_alloc_args args; |
|
|
|
add->frames = kvcalloc(count, sizeof(add->frames[0]), |
|
GFP_KERNEL); |
|
if (!add->frames) |
|
goto err; |
|
|
|
/* Remember the device, so we can free DMA memory. */ |
|
add->dma_dev = priv->dma_dev; |
|
|
|
args.dev = priv->dma_dev; |
|
args.coherent = !!(dma_flags & GNTDEV_DMA_FLAG_COHERENT); |
|
args.nr_pages = count; |
|
args.pages = add->pages; |
|
args.frames = add->frames; |
|
|
|
if (gnttab_dma_alloc_pages(&args)) |
|
goto err; |
|
|
|
add->dma_vaddr = args.vaddr; |
|
add->dma_bus_addr = args.dev_bus_addr; |
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} else |
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#endif |
|
if (gnttab_alloc_pages(count, add->pages)) |
|
goto err; |
|
|
|
for (i = 0; i < count; i++) { |
|
add->grants[i].domid = DOMID_INVALID; |
|
add->grants[i].ref = INVALID_GRANT_REF; |
|
add->map_ops[i].handle = INVALID_GRANT_HANDLE; |
|
add->unmap_ops[i].handle = INVALID_GRANT_HANDLE; |
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if (use_ptemod) { |
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add->kmap_ops[i].handle = INVALID_GRANT_HANDLE; |
|
add->kunmap_ops[i].handle = INVALID_GRANT_HANDLE; |
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} |
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} |
|
|
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add->index = 0; |
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add->count = count; |
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refcount_set(&add->users, 1); |
|
|
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return add; |
|
|
|
err: |
|
gntdev_free_map(add); |
|
return NULL; |
|
} |
|
|
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void gntdev_add_map(struct gntdev_priv *priv, struct gntdev_grant_map *add) |
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{ |
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struct gntdev_grant_map *map; |
|
|
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list_for_each_entry(map, &priv->maps, next) { |
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if (add->index + add->count < map->index) { |
|
list_add_tail(&add->next, &map->next); |
|
goto done; |
|
} |
|
add->index = map->index + map->count; |
|
} |
|
list_add_tail(&add->next, &priv->maps); |
|
|
|
done: |
|
gntdev_print_maps(priv, "[new]", add->index); |
|
} |
|
|
|
static struct gntdev_grant_map *gntdev_find_map_index(struct gntdev_priv *priv, |
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int index, int count) |
|
{ |
|
struct gntdev_grant_map *map; |
|
|
|
list_for_each_entry(map, &priv->maps, next) { |
|
if (map->index != index) |
|
continue; |
|
if (count && map->count != count) |
|
continue; |
|
return map; |
|
} |
|
return NULL; |
|
} |
|
|
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void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map) |
|
{ |
|
if (!map) |
|
return; |
|
|
|
if (!refcount_dec_and_test(&map->users)) |
|
return; |
|
|
|
if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { |
|
notify_remote_via_evtchn(map->notify.event); |
|
evtchn_put(map->notify.event); |
|
} |
|
|
|
if (map->pages && !use_ptemod) |
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unmap_grant_pages(map, 0, map->count); |
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gntdev_free_map(map); |
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} |
|
|
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/* ------------------------------------------------------------------ */ |
|
|
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static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data) |
|
{ |
|
struct gntdev_grant_map *map = data; |
|
unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT; |
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int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte; |
|
u64 pte_maddr; |
|
|
|
BUG_ON(pgnr >= map->count); |
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pte_maddr = arbitrary_virt_to_machine(pte).maddr; |
|
|
|
/* |
|
* Set the PTE as special to force get_user_pages_fast() fall |
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* back to the slow path. If this is not supported as part of |
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* the grant map, it will be done afterwards. |
|
*/ |
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if (xen_feature(XENFEAT_gnttab_map_avail_bits)) |
|
flags |= (1 << _GNTMAP_guest_avail0); |
|
|
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gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags, |
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map->grants[pgnr].ref, |
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map->grants[pgnr].domid); |
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gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags, |
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INVALID_GRANT_HANDLE); |
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return 0; |
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} |
|
|
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#ifdef CONFIG_X86 |
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static int set_grant_ptes_as_special(pte_t *pte, unsigned long addr, void *data) |
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{ |
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set_pte_at(current->mm, addr, pte, pte_mkspecial(*pte)); |
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return 0; |
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} |
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#endif |
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|
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int gntdev_map_grant_pages(struct gntdev_grant_map *map) |
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{ |
|
int i, err = 0; |
|
|
|
if (!use_ptemod) { |
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/* Note: it could already be mapped */ |
|
if (map->map_ops[0].handle != INVALID_GRANT_HANDLE) |
|
return 0; |
|
for (i = 0; i < map->count; i++) { |
|
unsigned long addr = (unsigned long) |
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pfn_to_kaddr(page_to_pfn(map->pages[i])); |
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gnttab_set_map_op(&map->map_ops[i], addr, map->flags, |
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map->grants[i].ref, |
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map->grants[i].domid); |
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gnttab_set_unmap_op(&map->unmap_ops[i], addr, |
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map->flags, INVALID_GRANT_HANDLE); |
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} |
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} else { |
|
/* |
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* Setup the map_ops corresponding to the pte entries pointing |
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* to the kernel linear addresses of the struct pages. |
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* These ptes are completely different from the user ptes dealt |
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* with find_grant_ptes. |
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* Note that GNTMAP_device_map isn't needed here: The |
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* dev_bus_addr output field gets consumed only from ->map_ops, |
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* and by not requesting it when mapping we also avoid needing |
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* to mirror dev_bus_addr into ->unmap_ops (and holding an extra |
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* reference to the page in the hypervisor). |
|
*/ |
|
unsigned int flags = (map->flags & ~GNTMAP_device_map) | |
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GNTMAP_host_map; |
|
|
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for (i = 0; i < map->count; i++) { |
|
unsigned long address = (unsigned long) |
|
pfn_to_kaddr(page_to_pfn(map->pages[i])); |
|
BUG_ON(PageHighMem(map->pages[i])); |
|
|
|
gnttab_set_map_op(&map->kmap_ops[i], address, flags, |
|
map->grants[i].ref, |
|
map->grants[i].domid); |
|
gnttab_set_unmap_op(&map->kunmap_ops[i], address, |
|
flags, INVALID_GRANT_HANDLE); |
|
} |
|
} |
|
|
|
pr_debug("map %d+%d\n", map->index, map->count); |
|
err = gnttab_map_refs(map->map_ops, map->kmap_ops, map->pages, |
|
map->count); |
|
|
|
for (i = 0; i < map->count; i++) { |
|
if (map->map_ops[i].status == GNTST_okay) |
|
map->unmap_ops[i].handle = map->map_ops[i].handle; |
|
else if (!err) |
|
err = -EINVAL; |
|
|
|
if (map->flags & GNTMAP_device_map) |
|
map->unmap_ops[i].dev_bus_addr = map->map_ops[i].dev_bus_addr; |
|
|
|
if (use_ptemod) { |
|
if (map->kmap_ops[i].status == GNTST_okay) |
|
map->kunmap_ops[i].handle = map->kmap_ops[i].handle; |
|
else if (!err) |
|
err = -EINVAL; |
|
} |
|
} |
|
return err; |
|
} |
|
|
|
static int __unmap_grant_pages(struct gntdev_grant_map *map, int offset, |
|
int pages) |
|
{ |
|
int i, err = 0; |
|
struct gntab_unmap_queue_data unmap_data; |
|
|
|
if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { |
|
int pgno = (map->notify.addr >> PAGE_SHIFT); |
|
if (pgno >= offset && pgno < offset + pages) { |
|
/* No need for kmap, pages are in lowmem */ |
|
uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno])); |
|
tmp[map->notify.addr & (PAGE_SIZE-1)] = 0; |
|
map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE; |
|
} |
|
} |
|
|
|
unmap_data.unmap_ops = map->unmap_ops + offset; |
|
unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL; |
|
unmap_data.pages = map->pages + offset; |
|
unmap_data.count = pages; |
|
|
|
err = gnttab_unmap_refs_sync(&unmap_data); |
|
if (err) |
|
return err; |
|
|
|
for (i = 0; i < pages; i++) { |
|
if (map->unmap_ops[offset+i].status) |
|
err = -EINVAL; |
|
pr_debug("unmap handle=%d st=%d\n", |
|
map->unmap_ops[offset+i].handle, |
|
map->unmap_ops[offset+i].status); |
|
map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE; |
|
} |
|
return err; |
|
} |
|
|
|
static int unmap_grant_pages(struct gntdev_grant_map *map, int offset, |
|
int pages) |
|
{ |
|
int range, err = 0; |
|
|
|
pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages); |
|
|
|
/* It is possible the requested range will have a "hole" where we |
|
* already unmapped some of the grants. Only unmap valid ranges. |
|
*/ |
|
while (pages && !err) { |
|
while (pages && |
|
map->unmap_ops[offset].handle == INVALID_GRANT_HANDLE) { |
|
offset++; |
|
pages--; |
|
} |
|
range = 0; |
|
while (range < pages) { |
|
if (map->unmap_ops[offset + range].handle == |
|
INVALID_GRANT_HANDLE) |
|
break; |
|
range++; |
|
} |
|
err = __unmap_grant_pages(map, offset, range); |
|
offset += range; |
|
pages -= range; |
|
} |
|
|
|
return err; |
|
} |
|
|
|
/* ------------------------------------------------------------------ */ |
|
|
|
static void gntdev_vma_open(struct vm_area_struct *vma) |
|
{ |
|
struct gntdev_grant_map *map = vma->vm_private_data; |
|
|
|
pr_debug("gntdev_vma_open %p\n", vma); |
|
refcount_inc(&map->users); |
|
} |
|
|
|
static void gntdev_vma_close(struct vm_area_struct *vma) |
|
{ |
|
struct gntdev_grant_map *map = vma->vm_private_data; |
|
struct file *file = vma->vm_file; |
|
struct gntdev_priv *priv = file->private_data; |
|
|
|
pr_debug("gntdev_vma_close %p\n", vma); |
|
if (use_ptemod) { |
|
WARN_ON(map->vma != vma); |
|
mmu_interval_notifier_remove(&map->notifier); |
|
map->vma = NULL; |
|
} |
|
vma->vm_private_data = NULL; |
|
gntdev_put_map(priv, map); |
|
} |
|
|
|
static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma, |
|
unsigned long addr) |
|
{ |
|
struct gntdev_grant_map *map = vma->vm_private_data; |
|
|
|
return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT]; |
|
} |
|
|
|
static const struct vm_operations_struct gntdev_vmops = { |
|
.open = gntdev_vma_open, |
|
.close = gntdev_vma_close, |
|
.find_special_page = gntdev_vma_find_special_page, |
|
}; |
|
|
|
/* ------------------------------------------------------------------ */ |
|
|
|
static bool gntdev_invalidate(struct mmu_interval_notifier *mn, |
|
const struct mmu_notifier_range *range, |
|
unsigned long cur_seq) |
|
{ |
|
struct gntdev_grant_map *map = |
|
container_of(mn, struct gntdev_grant_map, notifier); |
|
unsigned long mstart, mend; |
|
int err; |
|
|
|
if (!mmu_notifier_range_blockable(range)) |
|
return false; |
|
|
|
/* |
|
* If the VMA is split or otherwise changed the notifier is not |
|
* updated, but we don't want to process VA's outside the modified |
|
* VMA. FIXME: It would be much more understandable to just prevent |
|
* modifying the VMA in the first place. |
|
*/ |
|
if (map->vma->vm_start >= range->end || |
|
map->vma->vm_end <= range->start) |
|
return true; |
|
|
|
mstart = max(range->start, map->vma->vm_start); |
|
mend = min(range->end, map->vma->vm_end); |
|
pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", |
|
map->index, map->count, |
|
map->vma->vm_start, map->vma->vm_end, |
|
range->start, range->end, mstart, mend); |
|
err = unmap_grant_pages(map, |
|
(mstart - map->vma->vm_start) >> PAGE_SHIFT, |
|
(mend - mstart) >> PAGE_SHIFT); |
|
WARN_ON(err); |
|
|
|
return true; |
|
} |
|
|
|
static const struct mmu_interval_notifier_ops gntdev_mmu_ops = { |
|
.invalidate = gntdev_invalidate, |
|
}; |
|
|
|
/* ------------------------------------------------------------------ */ |
|
|
|
static int gntdev_open(struct inode *inode, struct file *flip) |
|
{ |
|
struct gntdev_priv *priv; |
|
|
|
priv = kzalloc(sizeof(*priv), GFP_KERNEL); |
|
if (!priv) |
|
return -ENOMEM; |
|
|
|
INIT_LIST_HEAD(&priv->maps); |
|
mutex_init(&priv->lock); |
|
|
|
#ifdef CONFIG_XEN_GNTDEV_DMABUF |
|
priv->dmabuf_priv = gntdev_dmabuf_init(flip); |
|
if (IS_ERR(priv->dmabuf_priv)) { |
|
int ret = PTR_ERR(priv->dmabuf_priv); |
|
|
|
kfree(priv); |
|
return ret; |
|
} |
|
#endif |
|
|
|
flip->private_data = priv; |
|
#ifdef CONFIG_XEN_GRANT_DMA_ALLOC |
|
priv->dma_dev = gntdev_miscdev.this_device; |
|
dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64)); |
|
#endif |
|
pr_debug("priv %p\n", priv); |
|
|
|
return 0; |
|
} |
|
|
|
static int gntdev_release(struct inode *inode, struct file *flip) |
|
{ |
|
struct gntdev_priv *priv = flip->private_data; |
|
struct gntdev_grant_map *map; |
|
|
|
pr_debug("priv %p\n", priv); |
|
|
|
mutex_lock(&priv->lock); |
|
while (!list_empty(&priv->maps)) { |
|
map = list_entry(priv->maps.next, |
|
struct gntdev_grant_map, next); |
|
list_del(&map->next); |
|
gntdev_put_map(NULL /* already removed */, map); |
|
} |
|
mutex_unlock(&priv->lock); |
|
|
|
#ifdef CONFIG_XEN_GNTDEV_DMABUF |
|
gntdev_dmabuf_fini(priv->dmabuf_priv); |
|
#endif |
|
|
|
kfree(priv); |
|
return 0; |
|
} |
|
|
|
static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, |
|
struct ioctl_gntdev_map_grant_ref __user *u) |
|
{ |
|
struct ioctl_gntdev_map_grant_ref op; |
|
struct gntdev_grant_map *map; |
|
int err; |
|
|
|
if (copy_from_user(&op, u, sizeof(op)) != 0) |
|
return -EFAULT; |
|
pr_debug("priv %p, add %d\n", priv, op.count); |
|
if (unlikely(gntdev_test_page_count(op.count))) |
|
return -EINVAL; |
|
|
|
err = -ENOMEM; |
|
map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */); |
|
if (!map) |
|
return err; |
|
|
|
if (copy_from_user(map->grants, &u->refs, |
|
sizeof(map->grants[0]) * op.count) != 0) { |
|
gntdev_put_map(NULL, map); |
|
return -EFAULT; |
|
} |
|
|
|
mutex_lock(&priv->lock); |
|
gntdev_add_map(priv, map); |
|
op.index = map->index << PAGE_SHIFT; |
|
mutex_unlock(&priv->lock); |
|
|
|
if (copy_to_user(u, &op, sizeof(op)) != 0) |
|
return -EFAULT; |
|
|
|
return 0; |
|
} |
|
|
|
static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv, |
|
struct ioctl_gntdev_unmap_grant_ref __user *u) |
|
{ |
|
struct ioctl_gntdev_unmap_grant_ref op; |
|
struct gntdev_grant_map *map; |
|
int err = -ENOENT; |
|
|
|
if (copy_from_user(&op, u, sizeof(op)) != 0) |
|
return -EFAULT; |
|
pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count); |
|
|
|
mutex_lock(&priv->lock); |
|
map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count); |
|
if (map) { |
|
list_del(&map->next); |
|
err = 0; |
|
} |
|
mutex_unlock(&priv->lock); |
|
if (map) |
|
gntdev_put_map(priv, map); |
|
return err; |
|
} |
|
|
|
static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv, |
|
struct ioctl_gntdev_get_offset_for_vaddr __user *u) |
|
{ |
|
struct ioctl_gntdev_get_offset_for_vaddr op; |
|
struct vm_area_struct *vma; |
|
struct gntdev_grant_map *map; |
|
int rv = -EINVAL; |
|
|
|
if (copy_from_user(&op, u, sizeof(op)) != 0) |
|
return -EFAULT; |
|
pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr); |
|
|
|
mmap_read_lock(current->mm); |
|
vma = find_vma(current->mm, op.vaddr); |
|
if (!vma || vma->vm_ops != &gntdev_vmops) |
|
goto out_unlock; |
|
|
|
map = vma->vm_private_data; |
|
if (!map) |
|
goto out_unlock; |
|
|
|
op.offset = map->index << PAGE_SHIFT; |
|
op.count = map->count; |
|
rv = 0; |
|
|
|
out_unlock: |
|
mmap_read_unlock(current->mm); |
|
|
|
if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0) |
|
return -EFAULT; |
|
return rv; |
|
} |
|
|
|
static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u) |
|
{ |
|
struct ioctl_gntdev_unmap_notify op; |
|
struct gntdev_grant_map *map; |
|
int rc; |
|
int out_flags; |
|
evtchn_port_t out_event; |
|
|
|
if (copy_from_user(&op, u, sizeof(op))) |
|
return -EFAULT; |
|
|
|
if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) |
|
return -EINVAL; |
|
|
|
/* We need to grab a reference to the event channel we are going to use |
|
* to send the notify before releasing the reference we may already have |
|
* (if someone has called this ioctl twice). This is required so that |
|
* it is possible to change the clear_byte part of the notification |
|
* without disturbing the event channel part, which may now be the last |
|
* reference to that event channel. |
|
*/ |
|
if (op.action & UNMAP_NOTIFY_SEND_EVENT) { |
|
if (evtchn_get(op.event_channel_port)) |
|
return -EINVAL; |
|
} |
|
|
|
out_flags = op.action; |
|
out_event = op.event_channel_port; |
|
|
|
mutex_lock(&priv->lock); |
|
|
|
list_for_each_entry(map, &priv->maps, next) { |
|
uint64_t begin = map->index << PAGE_SHIFT; |
|
uint64_t end = (map->index + map->count) << PAGE_SHIFT; |
|
if (op.index >= begin && op.index < end) |
|
goto found; |
|
} |
|
rc = -ENOENT; |
|
goto unlock_out; |
|
|
|
found: |
|
if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) && |
|
(map->flags & GNTMAP_readonly)) { |
|
rc = -EINVAL; |
|
goto unlock_out; |
|
} |
|
|
|
out_flags = map->notify.flags; |
|
out_event = map->notify.event; |
|
|
|
map->notify.flags = op.action; |
|
map->notify.addr = op.index - (map->index << PAGE_SHIFT); |
|
map->notify.event = op.event_channel_port; |
|
|
|
rc = 0; |
|
|
|
unlock_out: |
|
mutex_unlock(&priv->lock); |
|
|
|
/* Drop the reference to the event channel we did not save in the map */ |
|
if (out_flags & UNMAP_NOTIFY_SEND_EVENT) |
|
evtchn_put(out_event); |
|
|
|
return rc; |
|
} |
|
|
|
#define GNTDEV_COPY_BATCH 16 |
|
|
|
struct gntdev_copy_batch { |
|
struct gnttab_copy ops[GNTDEV_COPY_BATCH]; |
|
struct page *pages[GNTDEV_COPY_BATCH]; |
|
s16 __user *status[GNTDEV_COPY_BATCH]; |
|
unsigned int nr_ops; |
|
unsigned int nr_pages; |
|
bool writeable; |
|
}; |
|
|
|
static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt, |
|
unsigned long *gfn) |
|
{ |
|
unsigned long addr = (unsigned long)virt; |
|
struct page *page; |
|
unsigned long xen_pfn; |
|
int ret; |
|
|
|
ret = pin_user_pages_fast(addr, 1, batch->writeable ? FOLL_WRITE : 0, &page); |
|
if (ret < 0) |
|
return ret; |
|
|
|
batch->pages[batch->nr_pages++] = page; |
|
|
|
xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK); |
|
*gfn = pfn_to_gfn(xen_pfn); |
|
|
|
return 0; |
|
} |
|
|
|
static void gntdev_put_pages(struct gntdev_copy_batch *batch) |
|
{ |
|
unpin_user_pages_dirty_lock(batch->pages, batch->nr_pages, batch->writeable); |
|
batch->nr_pages = 0; |
|
batch->writeable = false; |
|
} |
|
|
|
static int gntdev_copy(struct gntdev_copy_batch *batch) |
|
{ |
|
unsigned int i; |
|
|
|
gnttab_batch_copy(batch->ops, batch->nr_ops); |
|
gntdev_put_pages(batch); |
|
|
|
/* |
|
* For each completed op, update the status if the op failed |
|
* and all previous ops for the segment were successful. |
|
*/ |
|
for (i = 0; i < batch->nr_ops; i++) { |
|
s16 status = batch->ops[i].status; |
|
s16 old_status; |
|
|
|
if (status == GNTST_okay) |
|
continue; |
|
|
|
if (__get_user(old_status, batch->status[i])) |
|
return -EFAULT; |
|
|
|
if (old_status != GNTST_okay) |
|
continue; |
|
|
|
if (__put_user(status, batch->status[i])) |
|
return -EFAULT; |
|
} |
|
|
|
batch->nr_ops = 0; |
|
return 0; |
|
} |
|
|
|
static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch, |
|
struct gntdev_grant_copy_segment *seg, |
|
s16 __user *status) |
|
{ |
|
uint16_t copied = 0; |
|
|
|
/* |
|
* Disallow local -> local copies since there is only space in |
|
* batch->pages for one page per-op and this would be a very |
|
* expensive memcpy(). |
|
*/ |
|
if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref))) |
|
return -EINVAL; |
|
|
|
/* Can't cross page if source/dest is a grant ref. */ |
|
if (seg->flags & GNTCOPY_source_gref) { |
|
if (seg->source.foreign.offset + seg->len > XEN_PAGE_SIZE) |
|
return -EINVAL; |
|
} |
|
if (seg->flags & GNTCOPY_dest_gref) { |
|
if (seg->dest.foreign.offset + seg->len > XEN_PAGE_SIZE) |
|
return -EINVAL; |
|
} |
|
|
|
if (put_user(GNTST_okay, status)) |
|
return -EFAULT; |
|
|
|
while (copied < seg->len) { |
|
struct gnttab_copy *op; |
|
void __user *virt; |
|
size_t len, off; |
|
unsigned long gfn; |
|
int ret; |
|
|
|
if (batch->nr_ops >= GNTDEV_COPY_BATCH) { |
|
ret = gntdev_copy(batch); |
|
if (ret < 0) |
|
return ret; |
|
} |
|
|
|
len = seg->len - copied; |
|
|
|
op = &batch->ops[batch->nr_ops]; |
|
op->flags = 0; |
|
|
|
if (seg->flags & GNTCOPY_source_gref) { |
|
op->source.u.ref = seg->source.foreign.ref; |
|
op->source.domid = seg->source.foreign.domid; |
|
op->source.offset = seg->source.foreign.offset + copied; |
|
op->flags |= GNTCOPY_source_gref; |
|
} else { |
|
virt = seg->source.virt + copied; |
|
off = (unsigned long)virt & ~XEN_PAGE_MASK; |
|
len = min(len, (size_t)XEN_PAGE_SIZE - off); |
|
batch->writeable = false; |
|
|
|
ret = gntdev_get_page(batch, virt, &gfn); |
|
if (ret < 0) |
|
return ret; |
|
|
|
op->source.u.gmfn = gfn; |
|
op->source.domid = DOMID_SELF; |
|
op->source.offset = off; |
|
} |
|
|
|
if (seg->flags & GNTCOPY_dest_gref) { |
|
op->dest.u.ref = seg->dest.foreign.ref; |
|
op->dest.domid = seg->dest.foreign.domid; |
|
op->dest.offset = seg->dest.foreign.offset + copied; |
|
op->flags |= GNTCOPY_dest_gref; |
|
} else { |
|
virt = seg->dest.virt + copied; |
|
off = (unsigned long)virt & ~XEN_PAGE_MASK; |
|
len = min(len, (size_t)XEN_PAGE_SIZE - off); |
|
batch->writeable = true; |
|
|
|
ret = gntdev_get_page(batch, virt, &gfn); |
|
if (ret < 0) |
|
return ret; |
|
|
|
op->dest.u.gmfn = gfn; |
|
op->dest.domid = DOMID_SELF; |
|
op->dest.offset = off; |
|
} |
|
|
|
op->len = len; |
|
copied += len; |
|
|
|
batch->status[batch->nr_ops] = status; |
|
batch->nr_ops++; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u) |
|
{ |
|
struct ioctl_gntdev_grant_copy copy; |
|
struct gntdev_copy_batch batch; |
|
unsigned int i; |
|
int ret = 0; |
|
|
|
if (copy_from_user(©, u, sizeof(copy))) |
|
return -EFAULT; |
|
|
|
batch.nr_ops = 0; |
|
batch.nr_pages = 0; |
|
|
|
for (i = 0; i < copy.count; i++) { |
|
struct gntdev_grant_copy_segment seg; |
|
|
|
if (copy_from_user(&seg, ©.segments[i], sizeof(seg))) { |
|
ret = -EFAULT; |
|
goto out; |
|
} |
|
|
|
ret = gntdev_grant_copy_seg(&batch, &seg, ©.segments[i].status); |
|
if (ret < 0) |
|
goto out; |
|
|
|
cond_resched(); |
|
} |
|
if (batch.nr_ops) |
|
ret = gntdev_copy(&batch); |
|
return ret; |
|
|
|
out: |
|
gntdev_put_pages(&batch); |
|
return ret; |
|
} |
|
|
|
static long gntdev_ioctl(struct file *flip, |
|
unsigned int cmd, unsigned long arg) |
|
{ |
|
struct gntdev_priv *priv = flip->private_data; |
|
void __user *ptr = (void __user *)arg; |
|
|
|
switch (cmd) { |
|
case IOCTL_GNTDEV_MAP_GRANT_REF: |
|
return gntdev_ioctl_map_grant_ref(priv, ptr); |
|
|
|
case IOCTL_GNTDEV_UNMAP_GRANT_REF: |
|
return gntdev_ioctl_unmap_grant_ref(priv, ptr); |
|
|
|
case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: |
|
return gntdev_ioctl_get_offset_for_vaddr(priv, ptr); |
|
|
|
case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: |
|
return gntdev_ioctl_notify(priv, ptr); |
|
|
|
case IOCTL_GNTDEV_GRANT_COPY: |
|
return gntdev_ioctl_grant_copy(priv, ptr); |
|
|
|
#ifdef CONFIG_XEN_GNTDEV_DMABUF |
|
case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS: |
|
return gntdev_ioctl_dmabuf_exp_from_refs(priv, use_ptemod, ptr); |
|
|
|
case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED: |
|
return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr); |
|
|
|
case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS: |
|
return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr); |
|
|
|
case IOCTL_GNTDEV_DMABUF_IMP_RELEASE: |
|
return gntdev_ioctl_dmabuf_imp_release(priv, ptr); |
|
#endif |
|
|
|
default: |
|
pr_debug("priv %p, unknown cmd %x\n", priv, cmd); |
|
return -ENOIOCTLCMD; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) |
|
{ |
|
struct gntdev_priv *priv = flip->private_data; |
|
int index = vma->vm_pgoff; |
|
int count = vma_pages(vma); |
|
struct gntdev_grant_map *map; |
|
int err = -EINVAL; |
|
|
|
if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) |
|
return -EINVAL; |
|
|
|
pr_debug("map %d+%d at %lx (pgoff %lx)\n", |
|
index, count, vma->vm_start, vma->vm_pgoff); |
|
|
|
mutex_lock(&priv->lock); |
|
map = gntdev_find_map_index(priv, index, count); |
|
if (!map) |
|
goto unlock_out; |
|
if (use_ptemod && map->vma) |
|
goto unlock_out; |
|
refcount_inc(&map->users); |
|
|
|
vma->vm_ops = &gntdev_vmops; |
|
|
|
vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP; |
|
|
|
if (use_ptemod) |
|
vma->vm_flags |= VM_DONTCOPY; |
|
|
|
vma->vm_private_data = map; |
|
if (map->flags) { |
|
if ((vma->vm_flags & VM_WRITE) && |
|
(map->flags & GNTMAP_readonly)) |
|
goto out_unlock_put; |
|
} else { |
|
map->flags = GNTMAP_host_map; |
|
if (!(vma->vm_flags & VM_WRITE)) |
|
map->flags |= GNTMAP_readonly; |
|
} |
|
|
|
if (use_ptemod) { |
|
map->vma = vma; |
|
err = mmu_interval_notifier_insert_locked( |
|
&map->notifier, vma->vm_mm, vma->vm_start, |
|
vma->vm_end - vma->vm_start, &gntdev_mmu_ops); |
|
if (err) { |
|
map->vma = NULL; |
|
goto out_unlock_put; |
|
} |
|
} |
|
mutex_unlock(&priv->lock); |
|
|
|
if (use_ptemod) { |
|
/* |
|
* gntdev takes the address of the PTE in find_grant_ptes() and |
|
* passes it to the hypervisor in gntdev_map_grant_pages(). The |
|
* purpose of the notifier is to prevent the hypervisor pointer |
|
* to the PTE from going stale. |
|
* |
|
* Since this vma's mappings can't be touched without the |
|
* mmap_lock, and we are holding it now, there is no need for |
|
* the notifier_range locking pattern. |
|
*/ |
|
mmu_interval_read_begin(&map->notifier); |
|
|
|
map->pages_vm_start = vma->vm_start; |
|
err = apply_to_page_range(vma->vm_mm, vma->vm_start, |
|
vma->vm_end - vma->vm_start, |
|
find_grant_ptes, map); |
|
if (err) { |
|
pr_warn("find_grant_ptes() failure.\n"); |
|
goto out_put_map; |
|
} |
|
} |
|
|
|
err = gntdev_map_grant_pages(map); |
|
if (err) |
|
goto out_put_map; |
|
|
|
if (!use_ptemod) { |
|
err = vm_map_pages_zero(vma, map->pages, map->count); |
|
if (err) |
|
goto out_put_map; |
|
} else { |
|
#ifdef CONFIG_X86 |
|
/* |
|
* If the PTEs were not made special by the grant map |
|
* hypercall, do so here. |
|
* |
|
* This is racy since the mapping is already visible |
|
* to userspace but userspace should be well-behaved |
|
* enough to not touch it until the mmap() call |
|
* returns. |
|
*/ |
|
if (!xen_feature(XENFEAT_gnttab_map_avail_bits)) { |
|
apply_to_page_range(vma->vm_mm, vma->vm_start, |
|
vma->vm_end - vma->vm_start, |
|
set_grant_ptes_as_special, NULL); |
|
} |
|
#endif |
|
} |
|
|
|
return 0; |
|
|
|
unlock_out: |
|
mutex_unlock(&priv->lock); |
|
return err; |
|
|
|
out_unlock_put: |
|
mutex_unlock(&priv->lock); |
|
out_put_map: |
|
if (use_ptemod) { |
|
unmap_grant_pages(map, 0, map->count); |
|
if (map->vma) { |
|
mmu_interval_notifier_remove(&map->notifier); |
|
map->vma = NULL; |
|
} |
|
} |
|
gntdev_put_map(priv, map); |
|
return err; |
|
} |
|
|
|
static const struct file_operations gntdev_fops = { |
|
.owner = THIS_MODULE, |
|
.open = gntdev_open, |
|
.release = gntdev_release, |
|
.mmap = gntdev_mmap, |
|
.unlocked_ioctl = gntdev_ioctl |
|
}; |
|
|
|
static struct miscdevice gntdev_miscdev = { |
|
.minor = MISC_DYNAMIC_MINOR, |
|
.name = "xen/gntdev", |
|
.fops = &gntdev_fops, |
|
}; |
|
|
|
/* ------------------------------------------------------------------ */ |
|
|
|
static int __init gntdev_init(void) |
|
{ |
|
int err; |
|
|
|
if (!xen_domain()) |
|
return -ENODEV; |
|
|
|
use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap); |
|
|
|
err = misc_register(&gntdev_miscdev); |
|
if (err != 0) { |
|
pr_err("Could not register gntdev device\n"); |
|
return err; |
|
} |
|
return 0; |
|
} |
|
|
|
static void __exit gntdev_exit(void) |
|
{ |
|
misc_deregister(&gntdev_miscdev); |
|
} |
|
|
|
module_init(gntdev_init); |
|
module_exit(gntdev_exit); |
|
|
|
/* ------------------------------------------------------------------ */
|
|
|